Mobile telephony may provide for wireless voice communication by mobile equipment used in a public land mobile network (PLMN). A user may utilize a mobile station to communicate with other entities that belong to the PLMN or another network that is coupled to the PLMN. The PLMN may itself, contain a number of different network domains. As the station travels from one network domain to another, so must the call handling responsibilities. The number and types of existing network domains continually increase with each one having associated capabilities and standards of communicating designed to match the objectives of the particular domain. Roaming between these different domains and utilization of their particular capabilities and standards may present a variety of challenges for handling calls of a mobile station.